Stupidity: Ultimately, it did wind up working. However when they shoved the antidote vial into Claire's purse and got George's attention so he would eat her, this was an insanely stupid move. 1. They had no way of knowing if he would actually choose to eat her if he even grabbed her in the first place. Before then he'd been crushing people and even threw the helicopter pilot miles off the building while they watched that happen. 2. The antidote was in a plastic polymer like tube designed to hold the substance inside it while submerged in liquid nitrogen containment. Even if the gorilla's stomach acid could eat through the vial to get to the antidote, it would take hours for it to get through a material like that. 3. Gorillas are herbivores, so it wouldn't have tried to eat a person in the first place. (01:17:55)
Stupidity: Nobody is ever going to take a nine-year-old child on a dangerous mission to locate and destroy a marauding, giant shark, a project that has already cost a number of lives.
Stupidity: When Greg volunteers to watch the security monitors to see if the creatures can affect people through a screen, no-one even thinks to remain in the room with him to cover up the monitors with a blanket, towel or something similar in case the creatures' power can be transmitted that way. They tied him to a chair to reduce his chances of committing suicide, so they certainly thought there was a possibility that he would be in danger.
Stupidity: During the auction, we see the dinosaurs are brought into the room and placed in the middle. Thus blocking half of the bidders from the auctioneer's view. (01:16:40)
Stupidity: They could've used the flying chopper thingy to kill off the armed guys when rescuing the kids off the train carriages. That way they could have made sure they got every single kid rather than rushing to just take the one containing Minho (which they messed up).
Stupidity: The coast cities should have an alarm that detects the Kaijuns. If they do, they should work when the beasts are few miles away from the shore in order to give the people time to get to the shelters. Instead of that there are still people on the streets in Japan and on the docks in Los Angeles (in the flashback) while the kaijuns arrive from the sea.
Stupidity: At the very beginning of the movie, law enforcement is depicted executing a no-knock warrant. They approach a house surreptitiously and use a ram to open the door with no warning. When they arrived at the scene, all the cars and trucks in the raid were using flashing lights and wailing sirens. So much for the element of surprise.
Stupidity: A-X-L was supposed to be a highly sophisticated and intelligent robotic dog yet it let Sam torch it (without even trying to back away from the flames) and let drones attack it on two separate occasions, each resulting in A-X-L being incapacitated. A-X-L also fell and rolled down a hill, smashing itself. An advanced machine should be able to stay upright! It also seems odd and out-dated that a robot would run on gasoline.